Tractor brake



July 27, 1926; 1,594,203

J. A. JOHNSTON TRACT-OR BRAKE Filed August 6, 1924 20 limi Patented July 27, 1926.

TAKES A. JOHNSTON, 03' KENWOOD, CALIIOBKIA.

TRACTOR BRAKE.

Application filed August 6, 1924. Serlal Io. 780,477.

: My invention relates to a brake for tractors, the object to provide improved means operated by t e steering gear of the machine, adapted to appl the brake to that 8 one of the rear wheels w ich is on the side of the tractor toward which the turn is being made, thus retarding said wheel and facilitating turnin Y My brake is so constructed and adapted to 0 rate that, ordinaril the brake is not app ied in making a wi e turn to the left or to the right but when a very short turn is made, then turning of the steering wheel through a wider or greater arc, results in a plication of the brake, as aforesaid.

T e brake rod-for my invention is connected tothe arm 'onthe outside of the gear transmission ease, by preference, altho h the invention is not necessarily in this fashion.

It is to be understood that my invention isonly .used in combination with the steering gear and that I do not propose to brake or cramp one of the rear wheels except by 95 means operated from the usual steering gear and then, by preference, only when very short turns are made, as the brakes for both rear wheels are ordinarily unapplied when wide turns are made.

Only one embodiment of the invention is illustrated and it is to be understood that modifications may be resorted to without departing from the essential principle of the invenmi. d I

aecompanym rawmga: Pad lflisa .pla view of a tractor equi wi m improvements; (Fig. 2 is an enlarged perspective view of the brake mechanism an Fig. 3 is a detail side elevation of the operating connections. to the steering gear.

A tractor is shown, more or less conventionally, by the frame 1, the front steering wheels 2 and the rear wheels 3.

Any ordinaiy, or well knownsteerin gear 4 is provi ed for the front wheels, sai gear being operated by the well known steerlniiarm 5 operated b steering wheel 6.

y invention resides in combining with the means, my improved braking means will now be described.

A breke'rock shaft 7, which is suitably journaled in bearings 8 on the rear axle housing, or otherwise, has its bail 9 connected by brake rod 10 to the steerin arm 5, so thatthe brake rod 10 will he s 'fted and the brake rock shaft! turned when the steering arm 5 moves.

The rear wheels 3 are provided with brake drums 11 which are ada ted to be engaged by brake bands 12. The rake bands 12 are opened and closed by bell crank levers 13' to which the ends of the brake bands are pivoted at 14 and 15; The bell crank levers are connected by links-16 to arms 17 on the rock shaft 7.

:The leverages and clearances are such that during ordinary turns, the brake rod 10 would only be moved a sufiicient distanct to rock the shaft 7 through such a small are that the brake bands 12 will not bear on the drums 11: When, however, the steering wheel 6 is turned an unusual distance, as when the tractor is to make a very short turn, the brake rod 10 is moved and the brake band'12 on-that side of the tractor toward whichthe turn is tote made will be sufliciently contracted to embrace the. drum 11 but the brake band 12 on the other wheel will be let off or expanded. Consequently a' braking action will be efiected on the rear wheel which will be the so-called pivotal wheel and this results in so retarding the pivotal wheel that thevsharp turn is more quickly had than would be the case were no such braking action provided.

I claim:

In a brake for vehicles, the combination with inde ndent and oppositel acting frics tion band rakes for the rear w eels thereof, of a steering arm, a steering wheel for operating said arm, a rock shaft, a brake rod connectmg the rock shaft with the steerin arm, said rock shaft having levers whic are operatively connected to the respective brakes in op sitely coupled fashion for the purpose of tightening'the brake band on the pivotal wheel when a short turn is made,

while releasing the brake band of the other wheel, said bands being sufliciently loose so that the rock shaft will be insuflicientl turned to apply either brake when a wi e turn is made.

In testimony whereof I aflix my signature.

JAMES A. OIHSTON. 

